NIOSH
HAZARD REVIEW
Health
Effects of Occupational Exposure
to
Respirable Crystalline Silica
|
Table
22. Summary of data on lung tumors induced in rats by crystalline
silica
|
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|
Sample
and exposure conditions
|
Rat
strain
|
Sex
|
Incidence
of lung tumors*
|
Reference
|
Comments
|
|
|
Treated
rats
|
Controls
|
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|
Quartz
(Min-U-Sil 5):
|
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| Intratracheal
instillation of 7 mg/wk for 10 wk |
Sprague-Dawley
|
—†
|
6/36
|
0/58
|
Holland
et al. [1983] |
Treated
rats had 1 adenoma and 5 carcinomas. |
| Inhalation (nose only) of 12 ± 5 mg/m3 for up to 2 yr |
Fischer
344
|
F
|
20/60
|
0/54
|
Holland
et al. [1986] |
Treated
rats had 6 adenomas, 11 adenocarcinomas, and 3 epidermoid carcinomas. |
| Inhalation
of 51.6 mg/m3 for various durations; sacrificed at 24 months |
Fischer
344
|
F
|
10/53
|
0/47
|
Dagle
et al. [1986] |
Treated female rats had 10 epidermoid carcinomas. |
|
M
|
1/47
|
0/42
|
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| Intratracheal instillation of 20 mg in left lung; sacrificed at 12, 18, or 22 months, or found dead |
Fischer
344
|
M
|
30/67
|
1/75
|
Groth
et al. [1986] |
Treated
rats had 30 adenocarcinomas. Controls had 1 adenocarcinoma. |
|
Novaculite
(i.e., micro-crystalline quartz):
|
||||||
| Intratracheal instillation of 20 mg in left lung; sacrificed at 12, 18, or 22 months, or found dead |
Fischer
344
|
M
|
21/72
|
1/75
|
Groth
et al. [1986] |
Treated
rats had 20 adenocarcinomas and 1 epidermoid carcinoma. Controls had 1 adenocarcinoma. |
|
Raw
shale dust:
|
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| Inhalation (nose only) of 152 ± 51 mg/m3 (average quartz content: 8%–12%) |
Fischer
344
|
F
|
17/59
|
0/54
1/15‡ |
Holland
et al. [1986] |
Treated
rats had 2 adenomas, 8 adenocarcinomas, and 7 epidermoid carcinomas. Controls had 1 adenoma. |
|
Spent
shale dust:
|
||||||
| Inhalation
(nose only) of 176 ± 75 mg/m3 (average quartz content: 8%–12%) |
Fischer
344
|
F
|
11/59
|
0/54
1/15‡ |
Holland
et al. [1986] |
Treated
rats had 2 adenomas, 8 adenocarcinomas, and 1 epidermoid carcinoma. Controls had 1 adenoma. |
|
Quartz
(DQ12):
|
||||||
| Inhalation of 1 mg/m3 for 24 months |
Fischer
344
|
F
|
12/50
|
3/100
(male and female) |
Muhle
et al. [1989] |
Treated
female rats had 2 keratinizing cystic squamous cell tumors, 2 adenomas, and 8 adenocarcinomas. Treated male rats had 2 keratinizing cystic squamous cell tumors, 2 adenocarcinomas, 1 adenosquamous carcinoma, and 1 squamous cell carcinoma. Controls had 2 adenomas and 1 adenocarcinoma. |
|
Fischer
344
|
M
|
6/50
|
—
|
|||
| Inhalation (nose only) of 6 mg/m3 for 29 days followed by lifetime observation |
Wistar
|
F
|
62/82
|
0/85
|
Spiethoff
et al. [1992] |
Treated
rats had 8 adenomas, 17 bronchioloalveolar carcinomas, and 37 squamous cell carcinomas. |
| Inhalation (nose only) of 30 mg/m3 for 29 days followed by lifetime observation |
Wistar
|
F
|
69/82
|
0/85
|
Spiethoff
et al. [1992] |
Treated
rats had 13 adenomas, 26 bronchioloalveolar carcinomas, and 30 squamous cell carcinomas. |
| Source:
Adapted from Saffiotti et al. [1996]. *Number of lung tumors per number of rats observed. †Not reported. ‡Investigators used two control groups. |
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